Sensor network lifetime is largely affected by the energy consumption for data transmission from sensor nodes to a base station. We generalize and solve the problems of deploying multiple base stations in sensor networks using one-hop and multi-hop communication models to maximize network lifetime. Under the one-hop communication model, the sensors far away from base stations always deplete their energy much faster than others. We propose an optimal solution for small-scale networks and a heuristic approach for large-scale ones based on the smallest enclosing circle algorithm that deploys a base station at the geometric center of each cluster. Under the multi-hop communication model, both the base station locations and the data routing scheme need to be considered in maximizing network lifetime. We propose an iterative algorithm based on rigorous mathematical derivations and use linear programming to compute the optimal routing path for benchmark purposes. Extensive simulation results show superior network lifetime performance of the proposed deployment algorithms in comparison with existing ones.